I've got the 2F STUMBLES!

Hey Guys,
I've got a couple of questions regarding my 87 FJ 60 (stock drivetrain, smog, 203K mi). When climbing long/short, relatively steep paved/unpaved inclines the motor begins to stumble. The stumble does not start immediatley, but after plenty of throttle has been applied in the correct gear on the climb. It's a jerky on then off, on then off stumble that feels like a fuel shortage issue?? At first I thought it was linked to a faulty clutch, but after replacing it the problem still persists. I remeber some similar posts on this issue but was unable to locate them (sorry if I'm asking old ??'s). All of the emmisions eqpt. is in place, but I have a leaky PS pump :'(.
I'm leaning toward replacing the fuel pump and fliter. Is the a tough undertaking? I'm also leaning toward taking the Cruiser to a very trust worthy independent Toyota wrencher to let him sink his teeth into this problem. What do you all think?? carb, vaccum leak, smog pump, fuel pump/fltr, ignition sys.???
My hands are pretty much tied on this one, as the emmisions stuff gets a little deep for me. Any advice or comments is greatly appreciated.
Thanks

I'm thinking fuel filter. Usually when a fuel pump goes, it goes completely. Kind of like a water pump does. I'm thinking that it is the filter because you said it does it under acceleration and sounds like it is fuel starved. I'd start there first.

Thanks for the replies. I will probably go ahead and order an OEM fuel filter today and see where that gets me (probably no where w/ my luck). Anyone ever rebuilt a AISIN carb themselves? Hard job??
Once again thanks for the advice.

Have you checked the vac advance on the distributor, and the vaccuum hoses that connect to it to see that the advance moves freely and that the hoses are not cracked?

Rebuilding an Aisin carb is not too bad. Do it on a clean bench though and follow the kit's instructions. There are some tiny parts in there that you definitely need to keep track of. Dont forget to put the goo on the leather plunger cup.

I'm almost positive the vac line is in place from carb-->dist, but I will double check at lunch. I would think that if it was absent I would have a ton of other problems?? But once again, that is why I ask yall. Another ? I've had for some time is that is an exhaust manifold leak (not 100% sure its actually the manifold) something that needs immediate attention?? Its a ticking noise that follows accelleration

coming out of the dist there is a stubby piece of hose, and a screw in the stub. there is a spare (2 actually) hoses coming out from the vac port (don't know if this is the official name) off the intake manifold that go no where, and both are blocked (with the screw method)

PO did a very nasty engine swap 82 2f into a 76(actually it was his mech as he didn't like to play with car bits) AC hoses, old heater hoses etc that go nowhere, wires going no where.

The dist is from an australian 76 2f (at least a 76 cap fits it, and a post 78 cap does not)

The engine is an 82 2f with AC pump removed, unsure of which engine the carb (AISIN i believe) came off, believe it may have a vac port blocked off too.

I thought the Australian dists were non-vaccum advance models, and would not need a vaccum. I'm not sure.
Feel free to hijack any post I ever make, I learn can always learn from other's problems(as if I don't have enough of my own)

Pull the dist. cap. Where the vacuum diaphragm hooks up from the outside, there will be a small armature that connects to a ring inside the distributor. As vacuum increases it pulls on the diaphragm and the arm advancing the dist. If the ring is siezed up, the dist won't advance. Also pull the little snap ring and unscrew the diaphragm. After getting it off the dist. push and pull the little arm with your fingers over the hole to be sure that the little rubber diaphragm isnt cracked. You should feel just a little bit of suction if it is ok.